25 results about "Ultrasonic lamb waves" patented technology

This invention discloses a method and apparatus for cementing quality inspection based on ultrasonic Lamb waves. The method includes: acquiring a first ultrasonic Lamb wave signal received by a first receiver and a second ultrasonic Lamb wave signal received by a second receiver; calculating the first wave energy of a zero-order symmetric Lamb wave within a first time window of the first ultrasonic Lamb wave signal, and calculating the second wave energy of a zero-order symmetric Lamb wave within a second time window of the second ultrasonic Lamb wave signal; calculating the attenuation rate of the zero-order symmetric Lamb wave based on the first wave energy, the second wave energy, a first distance, and a second distance; comparing the attenuation rate with a pre-generated attenuation rate threshold, and determining the external medium properties based on the comparison result. This approach improves the accuracy of cementing quality inspection; and it allows for independent cementing quality evaluation without the need for combined acoustic impedance information, simplifying the cementing quality inspection process and improving its efficiency.

The invention discloses a symmetric path-based Lamb wave non-reference damage detection imaging method and system, and relates to the technical field of ultrasonic Lamb wave non-destructive detection and imaging, and the method comprises the steps: obtaining a preset symmetrically arranged sensor array, obtaining a response signal of a receiving sensor of each path based on a preset excitation signal, the response signals of the symmetrical paths are subjected to difference processing to obtain difference signals; calculating a wave packet of the difference signal by adopting Hilbert transform on the difference signal, extracting a scattered wave packet and a direct wave packet based on the wave packet of the difference signal, and respectively calculating the flight time of the scattered wave packet and the flight time of the direct wave packet; based on the flight time of the scattered wave packet and the flight time of the direct wave packet, calculating an elliptical orbit of the defect on each path, and based on the elliptical orbit of the defect on each path and by utilizing a spatial distribution function, obtaining defect pixel points in the imaging area; and the defect pixel points in the imaging area are subjected to weighted fusion to obtain a damage positioning imaging picture, so that the Lamb wave non-reference imaging of the damage is realized, and the detection efficiency is improved.

The invention relates to a thick-wall pressure vessel inner wall damage detection method based on a low-frequency ultrasonic phase control imaging algorithm, which comprises the following steps: calculating to obtain an ultrasonic Lamb wave frequency dispersion curve of a thick-wall plate-shaped structure, and selecting a low-frequency guided wave frequency; determining parameter configuration of array elements of the phased array according to the low-frequency guided wave frequency, and arranging the array elements on the outer wall of the pressure vessel; exciting a low-frequency Lamb wave signal, and collecting FMC data through phased array elements, including echo signal data of each array element; frequency dispersion compensation processing is carried out on the acquired FMC data, and a phase coherence factor of each imaging pixel point is calculated; and adopting a TFM (Time Frequency Modulation) algorithm based on phase coherence factor weighting to carry out delay weighted reconstruction on the compensated FMC data to obtain an imaging and positioning result of the damage defect of the inner wall of the pressure vessel. Compared with the prior art, the problems of guided wave propagation frequency dispersion effect, complex mode, low signal-to-noise ratio and the like can be solved, and high-precision imaging positioning of inner wall damage defects is realized.

The invention discloses a method for inverting the velocity of a cementing medium after casing based on ultrasonic Lamb waves, and relates to the field of geophysical logging. According to the method, ultrasonic Lamb wave logging and ultrasonic pulse reflection logging are carried out at all depth points through a post-casing scanning imaging logging instrument, waveform records at all the depth points are obtained, the thickness of a casing in the specified direction at all the depth points and acoustic impedance of a post-casing cementing medium are calculated in an inversion mode, and then the thickness of the casing in the specified direction at all the depth points and the acoustic impedance of the post-casing cementing medium are calculated on the basis of the ultrasonic Lamb wave logging waveform records. For each specified orientation of each depth point, Fourier transform is carried out on the full waveform of the near-bending Lamb wave and the full waveform of the far-bending Lamb wave, the phase difference of the far-bending Lamb wave and the far-bending Lamb wave is calculated, group delay processing is carried out, the working frequency band of the imaging logging instrument is scanned after combination, and the phase difference of the far-bending Lamb wave and the near-bending Lamb wave is calculated; and frequency values corresponding to the minimum values of the group delays at all the directions of all the depth points are obtained, and after a frequency set is obtained, the wave velocity and the medium type of the cementing medium after casing are determined according to the frequency values at all the directions in the frequency set, the frequency number of the minimum values and the acoustic impedance value.

The invention discloses a multi-modal ultrasonic Lamb wave imaging spatial resolution quantification method, and relates to the technical field of ultrasonic Lamb wave imaging, and the method specifically comprises the steps: 1, employing an array transducer to carry out point-by-point excitation and receiving on the basis of a full-focus method data collection mode, collecting complete full-matrix data, building a multi-modal Lamb wave propagation model, and carrying out the calculation of the multi-modal Lamb wave propagation model; the method comprises the following steps: step 1, constructing a corresponding Fisher information matrix based on partial derivative information of each channel in combination with observation noise variance, and step 2, carrying out CRLB numerical calculation by adopting an MATLAB platform based on a derivation result of the Fisher information matrix. Physical relations among the defect imaging precision, the wavelength and the modal characteristics are established theoretically, and a quantitative basis is provided for multi-modal selection and system design.

The present invention discloses a non-destructive testing stress evaluation method based on the static component of non-linear ultrasonic Lamb waves, belonging to the technical field of stress detection, including: S1. Construct a Rayleigh-Lamb equation introducing the non-linear theory of elastic bodies, and then determine the Lamb wave dispersion curve of the plate to be detected, and determine the excitation frequency and excitation mode of the excitation source according to the Lamb wave dispersion curve; S2. Excite the Lamb wave with the determined excitation frequency and excitation mode at one end of the stress detection area of the plate to be detected, and receive and extract the corresponding signal through the other end of the stress detection area; S3. Reverse the phase of the extracted signal, and re-excite and receive the signal with the reversed phase; S4. Process the received signal and calculate the ultrasonic non-linear coefficient as an evaluation parameter for the stress state of the plate to be detected. The fundamental wave frequency and mode of the present invention are more flexible in selection, can measure the relevant parameters of high-attenuation materials, and can effectively evaluate the early damage and stress state inside the materials.

The invention discloses an aluminum plate ultrasonic Lamb wave denoising method based on ICPO-VMD combined improvement of a wavelet threshold, and the method comprises the steps: collecting an ultrasonic echo signal of an aluminum plate, carrying out the adaptive optimization through an improved crown porcupine optimization algorithm, and obtaining an optimal parameter combination; performing variational mode decomposition on the ultrasonic echo signal by using the optimal parameter combination to obtain a plurality of intrinsic mode function components; calculating a correlation coefficient of each intrinsic mode function component and the original ultrasonic echo signal, and dividing all the components into a signal dominant component, a mixed component and a noise dominant component according to a preset correlation coefficient threshold; de-noising processing is carried out on the mixed component by adopting an improved wavelet threshold function; and reconstructing the signal dominant component and the denoised mixed component to obtain a denoised Lamb wave signal. According to the invention, high-fidelity and high-reliability de-noising processing of the ultrasonic Lamb wave signal of the aluminum plate is realized, and the accuracy and robustness of subsequent defect detection are improved.

The present invention discloses a method for actually measuring the attenuation coefficient of broadband laser ultrasonic Lamb waves in metal thin plates, belonging to the field of nondestructive testing. Data acquisition stage: Use a nanosecond laser to set a point source excitation on the surface of an aluminum alloy thin plate, and then use a scanning laser Doppler vibrometer (SLDV) to measure the wave field and collect linear wave field data. Data processing stage: Use the time-frequency analysis of continuous complex wavelet transform to obtain the time-frequency spectrum of the one-dimensional wave field signal. Determine the effective analysis range, including the time upper limit and the frequency upper limit. Extract the amplitude data represented by the intercept line. Attenuation characteristic analysis stage: Extract the peaks of the amplitude data at multiple distance points to obtain discrete points of the amplitude change with distance at a specific frequency. The present invention provides a method for actually measuring the attenuation characteristics of broadband laser ultrasonic Lamb waves. The solution of the attenuation coefficient provides an important theoretical reference for the calculation of the effective detection range and the selection of the filtering frequency of damage scattered waves.

The invention relates to the technical field of logging instruments, in particular to an ultrasonic lamb wave logging device and logging equipment. A logging device based on ultrasonic lamb waves comprises a probe which comprises a lamb wave transmitting transducer, a lamb wave receiving transducer, a resonance wave transmitting and receiving transducer and a slurry sound velocity measuring transducer; the circuit part comprises a transceiving system, is connected with each transducer in the probe and is used for transmitting excitation signals to the Lamb wave transmitting transducer, the resonance wave transmitting and receiving transducer and the slurry sound velocity measuring transducer in the probe in the logging process, so that the corresponding transducers transmit corresponding ultrasonic signals; echo signals of the Lamb wave receiving transducer, the resonance wave transmitting and receiving transducer and the slurry sound velocity measuring transducer are collected, and automatic gain processing is carried out on the echo signals. The continuous mud wave velocity in the shaft direction can be obtained when internal and external media of the casing are inversed, the detection efficiency and the calculation precision are high, the method is suitable for highly-deviated wells and horizontal wells, and the construction environment is prevented from being limited.

The application relates to the field of nondestructive testing of aerospace composites, and provides a composite material detection method based on ultrasonic Lamb wave filtering back-projection imaging, which comprises the following steps: acquiring a Lamb wave signal passing through a composite material; denoising the Lamb wave signal to obtain an optimized Lamb wave signal; continuously wavelet transforming the optimized Lamb wave signal to acquire a time-of-flight parameter of the optimized Lamb wave signal in the composite material; and based on the time-of-flight parameter, combining a filtering back-projection method reconstruction algorithm to acquire an internal image of the composite material, so as to detect internal defects of the composite material. The application utilizes the Lamb wave signal, the continuous wavelet transform and the filtering back-projection method to acquire a high-quality composite material internal damage image with few artifacts without the assistance of a baseline signal, and can effectively, quickly and accurately perform nondestructive testing on a plate-shaped composite material.

The application discloses a casing anisotropy measurement method based on ultrasonic Lamb waves. The application simulates by constructing an ultrasonic Lamb wave logging simulation model, respectively obtains the relationship between ultrasonic Lamb wave attenuation values, reflection amplitude values and casing corrosion degrees, then places the ultrasonic Lamb wave sound system in a preset target well section for actual measurement, obtains far and near waveform data and reflection waveform data, processes to obtain the envelope curves of the far and near waveforms and the reflection, calculates the casing corrosion degree value by using the reflection amplitude and casing corrosion degree relationship, determines the ultrasonic Lamb wave attenuation value after casing corrosion by using the ultrasonic Lamb wave attenuation value and casing corrosion degree relationship, combines the ultrasonic Lamb wave attenuation value of the casing without corrosion, determines the ultrasonic Lamb wave attenuation amount, calculates the difference value between the far and near waveform attenuation values and the ultrasonic Lamb wave attenuation amount, and obtains the real ultrasonic Lamb wave attenuation value. The application eliminates the influence of casing anisotropy on ultrasonic Lamb wave attenuation, and realizes accurate measurement of casing anisotropy.

The application relates to an acoustic metamaterial with a frequency-doubling filtering characteristic and a shape optimization method thereof, the optimization method comprising the following steps: constructing a two-dimensional finite element simulation model, the two-dimensional finite element simulation model comprising a main plate, a thin adhesive layer and an acoustic metamaterial, the acoustic metamaterial having an initial structure, the initial structure being periodically arranged by an initial unit cell structure, and a free-shape boundary being arranged in the initial structure; constructing an optimization model according to a target that a fundamental frequency is a passband and a frequency double is a stopband; adjusting the free-shape boundary on the basis of the initial structure by using a moving asymptote method; and calculating to obtain an optimal structure of the acoustic metamaterial. Compared with the prior art, the application not only ensures that the optimization target can be achieved, but also reduces the complexity of the structure, facilitates processing and manufacturing, and the designed acoustic metamaterial has the frequency-doubling filtering characteristic, and can effectively filter the inevitable system nonlinearity in nonlinear ultrasonic Lamb wave detection.

This invention discloses a method for inverting the velocity of the cemented medium behind the casing based on ultrasonic Lamb waves, relating to the field of geophysical logging. This invention utilizes a back-casing scanning imaging logging instrument to perform ultrasonic Lamb wave logging and ultrasonic pulse reflection logging at various depth points, acquiring waveform records at each depth point. The casing thickness and acoustic impedance of the cemented medium behind the casing at specified azimuths are inverted and calculated. Based on the ultrasonic Lamb wave logging waveform records, Fourier transforms are performed on the near-curved and far-curved Lamb wave full-wave waveforms at each specified azimuth of each depth point, calculating the phase difference between near and far-curved Lamb waves and performing group delay processing. Combining this with the operating frequency band of the back-casing scanning imaging logging instrument, the frequency values ​​corresponding to the minimum values ​​of the group delay at each azimuth of each depth point are obtained. After obtaining the frequency set, the wave velocity and medium type of the cemented medium behind the casing are determined based on the frequency values, the number of minimum frequencies, and the acoustic impedance values ​​at each azimuth of the frequency set.

The invention relates to a guided wave mode converter with an efficient mode conversion characteristic and a shape optimization method thereof, and the method comprises the following steps: constructing an integral finite element model of an initial guided wave mode converter which comprises an aluminum plate, a thin bonding layer and a guided wave mode converter, and the structure of the initial guided wave mode converter is periodically arranged triangular elements, the guided wave mode converter is adhered to the two sides of the aluminum plate through the thin adhesive layer; constructing an optimization model of the guided wave mode converter by taking the efficient mode conversion characteristic as a target, and performing grid division on the optimization model; setting a target function and a constraint condition, and adjusting the geometrical shape of the triangular primitive according to the target function and the constraint condition by adopting a moving asymptote method to obtain an optimal value; and obtaining a final optimized shape of the guided wave mode converter according to the optimal value. Compared with the prior art, the A0 mode is converted into the pure S0 mode while high transmissivity is guaranteed, so that the problem of mutual interference of different modes in low-frequency ultrasonic Lamb wave detection is solved.

The present invention discloses a method for quantifying the spatial resolution of multimodal ultrasonic Lamb wave imaging, which relates to the technical field of ultrasonic Lamb wave imaging. The method specifically comprises the following steps: first, based on a full-focusing data acquisition method, an array transducer is used for point-by-point excitation and reception, complete full-matrix data is acquired, and a multimodal Lamb wave propagation model is established; second, based on partial derivative information of each channel and in combination with the observed noise variance, a corresponding Fisher information matrix is ​​constructed; and third, based on the derivation result of the Fisher information matrix, a MATLAB platform is used for numerical calculation of CRLB. The present invention introduces a minimum variance expression for deriving defect positioning in Lamb wave imaging from statistical estimation theory, theoretically establishes a physical relationship between defect imaging accuracy and wavelength and modal characteristics, and provides a quantitative basis for multimodal selection and system design.

The application discloses a large-interval array ultrasonic signal anti-symmetry Lamb wave dispersion extraction method for a cased well, an electronic device and a program product. The method comprises the following steps: constructing a Hankel matrix according to a frequency domain space sequence of a large-interval ultrasonic Lamb wave array signal, and then solving spatial poles; constructing a Vandermonde matrix according to the spatial poles, and then solving real complex amplitudes of the spatial poles; performing adaptive dynamic phase unwrapping on the spatial poles according to a phase velocity of a prior A0 mode, and obtaining phase velocities and spatial attenuation coefficients of all spatial poles in a full frequency band; selecting an initial anchor point according to the real complex amplitudes of the poles in a dynamic pole library; eliminating cross modes and noise interference according to the initial anchor point and a monotonicity constraint of the phase velocity; eliminating artifact points according to a difference between an error mean of imaginary parts of the dynamic poles and a fitting curve and a fitting variance, and obtaining a final A0 mode dispersion curve. The application effectively suppresses spatial aliasing and mode cross artifact.

The invention discloses an air coupling Lamb wave detection device and method for a ceramic matrix composite component, and belongs to the technical field of ultrasonic nondestructive detection. Comprising a control system, a six-degree-of-freedom industrial robot, a detection system arranged at the tail end of the six-degree-of-freedom industrial robot, and a ceramic matrix composite spraying pipe arranged at the end, away from the six-degree-of-freedom industrial robot, of the detection system. The spray pipe clamping mechanism is arranged below the ceramic matrix composite spray pipe; the spray pipe rotating mechanism is arranged below the spray pipe clamping mechanism; through mutual cooperation of all the parts, an air coupling ultrasonic lamb wave detection method and an automatic detection system are applied, and automatic detection of internal defects of the ceramic matrix composite spraying pipe of the airspace engine is achieved. According to the air coupling Lamb wave detection device and method for the ceramic-based composite component, nondestructive evaluation is carried out on the internal quality of the ceramic-based composite spray pipe, and the device and method have important significance on development of the spaceflight cause.

The invention relates to the technical field of fatigue crack nondestructive testing, in particular to an orthotropic steel bridge deck fatigue crack Lamb wave signal fusion processing method which comprises the steps that theoretical analysis and numerical simulation are conducted on an orthotropic steel bridge deck ultrasonic Lamb wave signal, and Lamb wave detection basic parameters are obtained; based on Lamb wave detection basic parameters and original signals, baseline correction is carried out on the Lamb wave signals, signal baseline drift caused by the load effect is eliminated, and to-be-separated signals without baseline interference are obtained; for a to-be-separated signal without baseline interference, performing multi-mode separation on the Lamb wave signal after baseline correction, extracting a low-order symmetric vibration mode signal and a low-order anti-symmetric vibration mode signal of the Lamb wave, and obtaining a single-mode original signal; and processing the separated single-mode signal, and correcting the frequency dispersion compensation process by combining with the thickness change caused by the fatigue crack damage of the orthotropic steel bridge deck to obtain a single-mode non-frequency dispersion signal. And a high-quality detection signal can still be obtained in a non-ideal environment.

This invention discloses a cement velocity inversion method based on arrayed ultrasonic Lamb waves, belonging to the field of oil and gas well exploration and development technology. It solves the technical problems of low computational efficiency and limited applicable velocity range in cement velocity inversion algorithms. The method includes: performing spatiotemporal preprocessing on the array signal to obtain the target guided wave mode, and extracting the complex dispersion curve of the target guided wave mode; constructing a three-layer planar medium model and deriving the dispersion matrix; setting the acoustic parameters of the well fluid and casing, generating multiple sets of initial value sequences for the parameters to be inverted, and calculating the determinant of the dispersion matrix; constructing a loss function, iteratively updating the parameters to be inverted and repeating the process until the number of iterations reaches a preset iteration threshold; traversing all sets of initial value sequences and extracting the iteration parameters corresponding to the round in which the loss function reaches its minimum value. This invention broadens the applicable working conditions and universality, facilitates automated and batch processing, and improves computational efficiency.

The invention relates to a sound absorption metamaterial for near boundary damage ultrasonic imaging detection, a design method and an ultrasonic imaging detection method.The sound absorption metamaterial is composed of at least one sound absorption metamaterial unit, and the design method comprises the steps that the geometric parameter range and the material parameter range of the sound absorption metamaterial unit are determined according to the ultrasonic detection frequency; establishing a near-boundary defect ultrasonic lamb wave detection finite element model, and calculating the reflection phase and reflectivity of the sound absorption metamaterial unit under different geometric parameters and material parameters; according to the multiple scattering theory, the number of the sound absorption metamaterial units is determined, so that the diffraction propagation mode of the sound absorption metamaterial only has a 0-order diffraction propagation mode; and determining optimal geometric parameters and material parameters of the sound absorption metamaterial unit. Compared with the prior art, the method has the advantages that the influence of high-energy boundary reflected waves on imaging results is reduced, and the sensitivity and imaging accuracy of ultrasonic lamb wave detection of defects at the near boundary are improved.

To provide a technique capable of detecting internal damage even when a fiber-reinforced resin layer is thick.SOLUTION: A method for inspecting a high pressure tank in which a reinforcement layer formed by laminating a plurality of members is formed on an outer periphery of a tank container includes a wave transmission step of transmitting an ultrasonic wave of a Lamb wave to the reinforcement layer, a wave reception step of receiving a reflected wave of the ultrasonic wave, and a determination step of determining that damage has occurred inside the reinforcement layer when an intensity of the reflected wave after a lapse of a predetermined threshold time from the transmission of the ultrasonic wave is equal to or less than a predetermined threshold intensity.SELECTED DRAWING: Figure 2

The present application relates to a kind of sound-absorbing metamaterials for near boundary damage ultrasonic imaging detection and design method and ultrasonic imaging detection method, sound-absorbing metamaterials are made of at least 1 sound-absorbing metamaterial unit, design method includes: according to ultrasonic detection frequency, the geometric parameter range and material parameter range of sound-absorbing metamaterial unit are determined;Establish near boundary defect ultrasonic lamb wave detection finite element model, the reflection phase and reflectivity of sound-absorbing metamaterial unit under different geometric parameters and material parameters are calculated;According to multiple scattering theory, the number of sound-absorbing metamaterial unit is determined, so that the diffraction propagation mode of sound-absorbing metamaterial only exists 0 order diffraction propagation mode;The optimal geometric parameter and material parameter of sound-absorbing metamaterial unit are determined.Compared with prior art, the present application has the advantages of reducing the influence of high-energy boundary reflected wave on imaging result, improving the sensitivity and imaging accuracy of near boundary defect ultrasonic lamb wave detection and the like.

The application discloses an ultrasonic Lamb wave dispersion compensation method and device based on convolutional auto-encoding, which comprises the following steps: S1, constructing a convolutional auto-encoding network model applied to compensation of an ultrasonic Lamb wave dispersion signal; S2, constructing a training set data according to the time of flight of each wave packet of the ultrasonic Lamb wave dispersion signal of a multimodal multi-wave packet at different distances, and training the convolutional auto-encoding network model by using the training set data; S3, generating an ultrasonic Lamb wave test data set, testing the trained convolutional auto-encoding network model, and outputting a test result; and S4, reconstructing an ultrasonic Lamb wave signal according to the test result. The application realizes synchronous compensation of the ultrasonic Lamb wave dispersion signal of a multimodal multi-wave packet, captures the time of flight information of the dispersion signal wave packet under the condition of a multimodal multi-wave packet, can separate the superimposed wave packet, and realizes effective dispersion compensation of the ultrasonic Lamb wave signal in combination with an excitation signal waveform.

The invention discloses a laser ultrasonic Lamb wave signal noise reduction method for metal aluminum sheet defect detection. Comprising the following steps: collecting a Lamb wave signal to be measured, carrying out decomposition processing on the Lamb wave signal by adopting complete adaptive noise ensemble empirical mode decomposition (CEEMDAN), and solving the modal aliasing problem of a multi-order intrinsic mode (I MF) component by utilizing a Pearson coefficient method to obtain an I MF component without modal aliasing; calculating a permutation entropy value of each order of component, setting a threshold value, screening effective signal components, and performing primary reconstruction; performing stationary wavelet (SWT) decomposition processing on the primary reconstruction signal to obtain a low-frequency approximation coefficient and a high-frequency detail coefficient; constraining the high-frequency detail coefficient through an L2 regularization method; and carrying out secondary reconstruction on the reserved approximation coefficient and the detail coefficient after L2 constraint to obtain a Lamb wave signal after final noise reduction. The signal quality of the Lamb wave signal is improved, and the accuracy of defect detection of the metal aluminum sheet is improved.

The present invention relates to the field of sensing and testing technologies, and specifically discloses a sparse reconstruction method for the Lamb wave dispersion characteristics of a composite material plate based on feature optimization. The method includes: during the piezoelectric excitation-laser reception experiment, collecting experimental data received at multiple points in different angular directions; performing signal preprocessing on the experimental data to obtain preprocessed experimental data; comparing and analyzing the preprocessed experimental data with the experimental data, and obtaining a scaling method based on the comparison and analysis results; constructing a sparse optimization model based on the sparsity of the signal in the frequency-wavenumber domain; combining the sparse optimization model and the scaling method, and using the alternating direction multiplier method to solve the sparse optimization model to obtain the frequency domain-wavenumber distribution, and extracting the dispersion curve based on the frequency domain-wavenumber distribution; performing sparse reconstruction on the ultrasonic Lamb wave dispersion curve in any direction in the composite material plate to be detected, and completing the sparse reconstruction method for the Lamb wave dispersion characteristics of the composite material plate based on feature optimization.